The process of preparing metallic matrix diamond tool bits by microwave pressureless sintering (MPS) was exclusively studied in this paper. The effects of the sintering temperature, the cold pressure, and the holding time on the mechanical properties of the bit were determined by using the response surface methodology (RSM) with Box-Behnken Design (BBD). In addition, with RSM, the second-order polynomial equation of mechanical properties was obtained. The solutions were well matched with the experimental values. This indicates that major variations in mechanical properties of the sintered sample could be predicted by the models, which shows that the applied model is accurate. Conventional pressureless sintering (CPS) experiments were also conducted to make a comparison. The experimental results showed that the MPS can enhance the mechanical properties of sintered samples. A possible MPS mechanism is proposed in this work after analyzing all the experimental results.

Microwave pressureless sintering (MPS) method is successfully applied in the fabrication of Cu based metallic matrix for diamond tools. The main purpose of this work is to obtain better mechanical properties when the metal binder of the diamond tools was prepared by the MPS method. The orthogonal experimental method is adopted to design the sintering process parameters. The optimized experimental conditions are suggested as 880 °C of sintering temperature, 375 MPa of cold pressure, and 35 min of withholding time. The contrastive investigation of the MPS and conventional pressureless sintering (CPS) are performed under optimized conditions. The microstructures information are obtained by scanning electron microscopy (SEM), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and the necessary mechanical properties, such as relative density, hardness, and flexural strength are tested. Experimental results show that the MPS method, compared with CPS, can significantly improve the mechanical properties of the metallic matrix. The factors of relative density, hardness, and flexural strength increase 1.25%, 3.86%, and 6.28%, respectively. The possible sintering mechanism of the MPS method is also discussed. This work may provide a reference for the fabrication of metal-based diamond tools by microwave heating method.

Seawater electrolysis is an ideal technology for obtaining clean energy—green hydrogen. Developing efficient bifunctional catalysts is crucial for hydrogen production through direct seawater electrolysis. Currently, metal substrates loaded with active catalysts are widely employed as electrodes for seawater electrolysis. However, the challenge of metal corrosion cannot be ignored. In this work, the boron-doped diamond (BDD) with excellent corrosion resistance was explored as a substrate for loading active catalysts in seawater electrolysis. A step-by-step electrodeposition method was used to fabricate the FeCoS/Ni/BDD electrode, effectively addressing the poor adhesion of the FeCoS active layer to the BDD substrate. The resulting electrode demonstrated interesting bifunctional catalytic performance, achieving oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) overpotentials of 425 mV and 360 mV, respectively, in alkaline simulated seawater (1 M KOH and 3.5 wt% NaCl) at a current density of 100 mA cm^− 2. Furthermore, by increasing the KOH concentration in the alkaline simulated seawater to 3 M, the OER and HER overpotentials of the electrode significantly decreased to 383 and 300 mV, respectively. This work offers a novel approach for utilizing BDD substrates in the design of corrosion-resistant electrodes for alkaline seawater electrolysis.

Platinum group metals (PGMs)—comprising platinum (Pt), palladium (Pd), rhodium (Rh), iridium (Ir), ruthenium (Ru), and osmium (Os)—are indispensable strategic materials for key industries, including automotive manufacturing, petrochemical engineering, and the new energy sector. Given the uneven global distribution of primary PGM reserves and the widening supply–demand gap, recovering PGMs from secondary sources—primarily metallurgical by-products and spent catalysts—has become a strategic priority. synergistic smelting, leveraging “multi-feedstock complementarity” and “multi-technology coupling,” offers an efficient approach to overcoming challenges associated with secondary resources, such as low grades, complex matrices, and refractory separation. This paper systematically reviews the technological evolution of synergistic smelting for PGMs recovery, focusing on three aspects: the characteristics and processing bottlenecks of PGMs-bearing secondary resources, the development trajectory of traditional metallurgical technologies, and innovative breakthroughs in microwave-assisted synergistic smelting. A comparative analysis between traditional and microwave-based technologies is conducted across four dimensions: resource adaptability, technical performance, environmental sustainability, and industrial maturity. Finally, the core challenges currently confronting microwave-assisted synergistic smelting and future directions for industrial demonstration are elaborated on. This study serves as a comprehensive reference for the efficient and sustainable recovery of PGMs, with significant implications for the circular economy and strategic resource security.

Dense lithium hydride (LiH) is widely used in neutron shielding applications for thermonuclear reactors and space systems due to its unique properties. However, traditional sintering methods often lead to cracking in LiH products. This study investigates the densification sintering of LiH using microwave technology. A multiphysics model was established based on the measured dielectric properties of LiH at different temperatures, allowing for a detailed analysis of the electromagnetic and thermal field distributions during the microwave heating of cylindrical LiH samples. The results indicate that the electric field distribution within the LiH is relatively uniform, with resistive losses concentrated primarily in the LiH region of the microwave cavity. LiH rapidly absorbs microwave energy, reaching the sintering temperature of 520 °C in just 415 s. Additionally, the temperature difference between the low- and high-temperature regions during the sintering process remains below 5 °C, demonstrating excellent uniform heating characteristics. The microwave sintering process enhances interface migration within the LiH samples, resulting in dense metallurgical bonding between grains. In summary, this research provides valuable insights and theoretical support for the rapid densification of LiH materials, highlighting the potential of microwave technology in improving material properties.